This invention relates to an electrical circuit and particularly to one that functions to detect the amount of ice accumulated in the ice bin of a refrigeration apparatus having an automatic ice making function.
Many modern freezers used in industrial and residential applications include automatic ice making systems which deposit ice cubes into an ice bin for storage. A means for controlling the output of these types of ice making systems is needed to enable ice being consumed to be replenished and to prevent the mechanism from overproducing. Many existing designs for such controls employ means for weighing the ice bin or employ paddle-type sensors which detect the height of the accumulated pile of ice cubes. Although these devices generally perform satisfactorily, it is desirable to provide an improved ice bin level sensor which controls an ice making machine and operates without moving parts.
In accordance with this invention, an ice bin sensor circuit is provided which enables the detection of the quantity of ice in an ice bin using a beam of infrared light which is interrupted when the ice bin is filled to capacity. The circuit automatically controls the ice making apparatus to maintain a desired quantity of available ice cubes. Although light interrupter circuits are well known, the circuit according to this invention is efficiently designed for its intended function and employs readily available and inexpensive components. In order to prevent improper operation due to transient interruptions of the light beam, the circuit includes a time delay function. The circuit further includes means for preventing improper operation caused by ambient light, and includes a mechanism for rapid testing of the circuit during production or in-the-field malfunction diagnosis.
Additional benefits and advantages of the present invention will become apparent to those skilled in the art to which this invention relates from the subsequent description of the preferred embodiment and the appended claims, taken in conjunction with the accompanying drawings.